Method for the production of fanshaped screw locks



Dec. 14; 1937. A, TH ODE 2,102,493

METHOD FOR THE PRODUCTION OF FAN SHAPED SCREW LOCKS Filed Aug. 19, 1932 H fizz/safer 192109 7710028 WK SQW.

' Patented Dec. 14, 1937 UNITED STATES ME'rnon ron THE raonvo'rron or FAN- SHAPED SCREW LOCKS Adolf Thodglamburg-Billbrook, Germany, as-

signor to Illinois Tool Works, Chicago. 111., a

corporation oi Illinois Application August 19, 1932, Serial No. 629,428

. In Germany April 25, 1932 36 Claims.

This invention relates to the locking of screws orbolts by means of a washer-like disc, the security being obtained in that the inner or outer circumference of the disc is separated into flaps 5 by inwardly directed incisions. These flaps are slightly inclined, and therefore form portions which are designed to oppose loosening of the nut or of'the screw bolt. It is not possible to obtain a satisfactory effect with the aid of such locking discs if screw or bolt has to be tightened very strongly, as the flaps are then pressed flat and no longer oppose resistance against backward rotation of the nut or of the bolt. It has been proposed, to avoid the pressing flat of the flaps by shaping and arranging the flaps in such a manner that their side edges overlap the one The edg of the-one flapthe other fan-like. bears then against the edge of the next lower flap. .In' this manner, a permanent oblique position of the flaps is ensured as the material on the sharp edges of the flap is double thick. The edges of the flaps-must therefore 'cut into the nut and the bolt and prevent back rotation of the nut. This fan-like: overlapping ofthe flaps has hitherto been obtained by means of a draw-- ing process. The inner edge of the perforated disc is, according to this process, drawn upward and then slit, thereupon the flaps thus produced are pressed down again into the plane of the disc. This manner of manufacture is comparable to a mistreatment of material and is un'- desirable for machine elements, which arepermanently submitted to high stresses. Many operations are further necessary so that the cost 35 of manufacture is increased. It has been further proposed, to produce the fan-shaped overlapping by enlarging the flaps by embossing- The inconvenience of this method is, that the alterations of shape occur at undesirable places. The 40 material swells owing to the compressing in radial direction. The overlapping obtainable by pressing is only very limited, as the disc cannot be made very thick for manufacturing reasons. -If the last-mentioned method is applied, the machine is excessively stressed as it strikes hard owing to the thinness of the material of the discs.

These inconveniences are thoroughly obviated by the method according to the invention. The fundamental idea is, to. produce the overlapping of the flaps by reducing the original diameter of the disc. This reducing can be obtained by deep drawing of the central portion of the disc. A second possibility is, to force the disc through a conical die. The last-mentioned method is preferably applied for discs with inner or outer rim of flaps. Other possibilities of reducing the diameter of the disc are, of course, not excluded,

- provided the object to produce the overlapping is attained. An important advantage of this 5 method is, that the degree oi. overlapping can' be regulated as desired. This is efiected by more or less reducing the diameter. It must further be mentioned, that during the reducing of the diameter of, the disc the flaps are notsubmitted to special stress. The method of manufacturing is as simple as possible and can be carried out within a very short time.

Several forms of locking discs produced according to the improved method are illustrated by way of example in the accompanying drawing, in which: v

Fig. 1 shows in top plan view a locking disc, slit on the outer edge.

Fig. 2 is a side elevation of Fig. 1. Fig. 3 shows in top plan view the locking dis shown in Fig. 1, the diameter of which has been reduced by deep drawing of the central portion. Fig. 4 is a side elevation of Fig. 3.

Fig. 5 shows in top plan view the finished disc. Fig. 6 is a side elevation of Fig. 5.

Fig. '1 shows in top plan view a finished looking disc of another .form of construction, designed for screws with sunk head.

Fig. 8 is a side elevation of Fig. 7. 2 e Fig. 9 shows in top plan view a locking disc with slit inner edge. Fig. '10 is a side elevation of Fig. 9.

Fig. 11 shows in section the die and punch for the production of the overlapping and a locking disc with outer rim of overlapping flaps.

' Fig. 12 is a similar view to Fig. 11, the stamp and die being designed to produce locking discs with overlapping flaps on the inner edge.

The radial slits 2 in the'outer edge of the disc I are .produced in the usual manner, the flaps, produced between every two slits being, at

" the same time, slightly distorted. In a'isubsequent operation the original diameter of the disc is reduced in order to produce the overlapping. 5 This reducing of the diameter can be eflected by deep drawing of the central portion of the disc 7 l, or by forcing the disc through a conical die 8. 'I'his'overlapping method is the most practical, and it can be suitably employed as well forv discs with flap rim on the outer edge as for discs with flap rim on the inner edge. The reducing of the diameter .of the disc may be obtained in any other manner than described, provided the Object is attained to reduce the disc diameter. r

During the reducing of the diameter of the disc a contraction of material takes place, which has the efiect on the flaps that they are pushed the one over the other, so that the overlapping .4 is produced. The degree of overlapping can be regulated within certain limits by more or less great reduction of the diameter. If the overlapping is obtained by deep drawing of the central portion of the disc, a cup-shaped indentation 3.is produced, which is finally stamped out by the punch, so that a central opening 5 is produced. If the overlapping is to be produced by forcing the disc through a conical die, theaperture 5 has to be made prior to the operation. For

screws and other machine elements with sunk heads it is advisable to make the disc conical as shown in Figs. '1 and 8. This conical shape can be produced by deep drawing, pressing or the like.

In discs with inner flap rim the central aperture 5 is first produced, whereupon the slits are cut, a certain inclination being given at the same time to these flaps. This disc is then forced through the conical die I in the direction-of the arrow A, by means of the punch I. The diameter of the disc is thus reduced and the flaps overlap more or less; The method and its variations can be applied not only for circular discs, but also for discs of any other shape.

Attention is also directed to the fact that when my improved method is employed, the adjacent margins of each pair of prongs are shiited circumierentially so as to produce an overlap which is substantially unirorm throughout the entire radial extent of the prongs. In other words,

when the washer is reduced in diameter as described above. the adjacent radial margins of each pair of prongs overlap so as to present a pair of work-engaging edges'which are parallel.

with each other and spaced from. and parallel with the plane or the annular body of the washer.

It will also be noted that in practicing my method the prongs always occupy aradial position with respect to the axis of the washer and that the roots of the prongs are maintained in substantially ,the same plane as the annular washer body. The unii'ormity in thickness of the prongsis not affected by the diameter redlmins processes compared with prior methods with which I am familiar, wherein an actual deformation of the material comprising the'prongs occurs and this deformation causes one section of the prong to be thinner than another. As an example of this deforming method, attention is directed to the method shown in the patent to Steinhorst, 1,816,551. Thus, in my washer the prongs are maintained in substantially their original state of consistency or uniform thickness.

By having a substantial overlap of the prongs at their roots as well as at their free extremities I preclude the possibility of the adjacent margins of the prongs being wedged together at their roo s. lap throughout the radial extent of the prongs to insure positive abutment along said entire radial extent when the washer is clamped against a work piece. This insures the presence of a plurality of work engaging edges or'ratchet teeth disposed in parallel relation to. the ;washer body.

It will be apparent from the foregoing description that my invention contemplates the provision of an improved ratchet type pronged lock washer which may be produced without subjecting the washer material to any deleterious strains or deformations. Obviously the invention is not In other words, I provide suflicient overjoining edges, said flaps being of the original thickness of the disc.

2. As a new article of manufacture, a lock washer comprising one piece of sheet metal which includes a conical band, said piece being open at the center; and a second hand having radial slits which form said secondhand into flaps, which latter are uniformly overlapped at their opposite edges over their entire radial extent and disposedin the zone of symmetry of the first mentioned band, said. flaps being of the original thickness of the sheet.

3. A method of making lock washers, consisting in providing in a washer slits which open to one boundary 'edge of the washer, turning the portions of the washer between the slits whereby to move the opposite edges of said portions partly out of the same alignment; and contracting the washer-at its other edge.

4. A method of making lock washers, consisting in providing slits in a washer, which slits open to one boundary edge of the washer, turning the portions of the washer between the slits where- 'by to move the opposite edges of each or said portions at least partly out of alignment, and contracting that portion'of the washer which adjoins the other boundary edge whereby to' overlap the first mentioned portions.

5. A method oi making a lock washer from a flat disc of material which includes an inner came and an outer endless edge, there being a'central opening in the'material which is bounded by said inner edge; consisting in providing radial slits in said material which lead to said outer edge to provide flaps, distorting said flaps to turn the opposite edges thereof out of the plane of the said disc, and overlapping adjacent flaps at the roots and also the free ends thereof while th stock remains in its flattened state.

6. A method of making a lock washer, which consists in forming an endless outer edge on a flat disc of metal, providing a central opening in the disc to form an inner endless ed e; slitting said disc radially on different lines, said slits.

. disc between the other endless edge and the opposite ends of said slits whereby to overlap said flaps at their adjoining edges. f

7. A method of making a lock washer, which consists in forming an endless outer edge on a flat disc of metal, providing a central opening inv the disc to form an inner endless edge; slitting said disc radially on dlflerent lines so that said slits lead at one of their respective ends to one of said edges whereby to provide flaps thereat, turning the adjoining edge portions oi the respective flaps at least limitedly out of the plane of the center of the disc, contracting said disc between the other endless edge and the opposite end of said slits, drawing said flaps inwardly to reduce the diameter of the disc, and thereby Overlapping said flaps at said adjoining edges. 7

8. A method of making a lock washer, which consists in forming a disc of sheet metal, forming a central opening in the disk to provide an annular band, slitting the outer portion of the band radiallyto provide flaps, turning the flaps slightly to move their opposite edges at least partly out of the planeof the disc, and forcing the disc through a conical die, whereby to contract the inner portion of the band and reduce the diameter of the disc, thereby to cause said flaps to be overlapped and disposed in the plane of symmetry of said inner portion.

9. The method of making lock washers which includes the steps of providing radial severances along the outer margin of an annular body of flat spring stock to provide a plurality of outer prongs, warping said prongs so as to present oppositely disposed work-engaging edges on opposite sides of the body, circumferentially shifting adjacent radial margins on each prong by reducing the diameter of the annular bodyso as to effect the overlapping of said margins without afl'ecting the uniform thickness of said prongs during said shifting, and maintaining the body in flattened annular form.

10. A look washer including a conical body of spring stock and a plurality ofprongs along the outer margin of said body, said prongs being .spring stock, and a plurality of prongs along the outer margin of said body, said prongs being warped so as to present work-engaging edges on opposite sides of said body, the adjacent margins of each pair of prongs being overlapped, the

overlap at the root being, substantially equal to the overlap at the free ends of the prongs.

12. The method of making lock washers which includes the step of forming a plurality of prongs along a margin of Ian annular washer blank, warping said'prongs to present work-engaging edges on opposite sides of the washer body, maintaining the roots of said prongs substantially within the plane of the washer body, and causing the adjacent margins of each pair of prongs to be disposed in overlapping relation by reducing the diameter of the annular washer body while maintaining the body of each prong uniform in thickness.

13. The'methodof making lock washers which includes the stepof producing an annular section of flat spring stock having a plurality of radial prongs along at least one margin thereof, reducing the diameter of said annular section so as to effect the overlapping of adjacent margins of said prongs, while maintaining the washer body in its flattened state.

14. The method of making lock washers which includes the step of marginally severing a section of flat spring stock so as to form a plurality of margin of said body, said prongs being of substantially the original consistency of the stock.

16. A lock washer including an annular body portion of spring stock, and a plurality of overlapping prongs provided along at least one margin thereof, the degree of overlap being substantially uniform over the entire radial extent of the prongs. v

17. The method of making lock washers'which consists in the step of marginally. severing a section of spring stock so'v asto form a plurality of marginal prongs, warping-said prongs so as to present work-engaging teeth on opposite sides of the body,'and reducing the inner diameter of the washer to effect an overlapping of adjacent margins of said prongs.

18. A method of making washers, said method including the steps of forming aplurality of prongs along the margin of an annular washer blank; reducing the diameter of the. blank so as to cause said prongs to overlap, and maintain-. ing the washer body in a flattened state.

19. The method of making lock washers which includes the steps of providing a section of stock having a plurality of separate adjacent marginal prongs and a continuous portion to which said prongs are joined; and reducing the diameter of said portion to effect an overlapping of adjacent prongs.

20. The method of making lock washers which includes the steps of providing a section of stock having a plurality of separate adjacent marginal prongs and a substantially circular continuous portion to which said prongs are joined; and then reducing the diameter of said continuous portion to eiiect an overlapping of adjacent prongs.

21s The method of making lock washers which includes the steps of providing an annular section of stock having a plurality of adjacent outer marginal prongs, and reducing the inner diameter of said section to effect an overlapping of adjacent prongs.

22. The method of making lock washers which includes the steps of providing an annular section of stock having a plurality of separate adjacent marginal prongs and a continuous portion to'which said prongs are joined; and reducing the diameter of said continuous portion to effect an overlapping of adjacent prongs.

23. The method of making lock washers which includes the steps of providing a section of stock having a plurality of separate adjacent marginal prongs and an annular portion to which said prongs are joined; and reducing the inner diameter of said annular portion to effect an overlapping of adjacent prongs.

24. The method of making lock washers which 25. A look washer including a substantially flat body portion of spring stock, a plurality of prongsv arranged inoverlapping relation along the outer margin of said body, said prongs being of sub- "stantially the original consistency of the stock.

26. A look washer including a substantially flat annular body portion of spring stock, a plurality of prongs arranged in overlapping relation along the outer margin of said body, said prongs being of substantially the original consistency of the stock.

27. The method of making lock washers which includes the steps of providing a section of flat stock having a plurality of twisted separate adjacent marginal prongs and a continuous portion to which said prongs are. joined; shifting adjacent prongs toward each other to effect an overlapping of adjacent margins of said prongs without affooting the uniform thickness of the prongs during the shifting; and maintaining said continuous portion substantially flat throughout said steps. 28. The method of making lock washers which includes the steps of providing a section of stock having a plurality of separate adjacent outermarginal prongs and a flat continuous portion to which said prongs are joined; reducing the diameter of said section to effect an overlapping of adjacent margins of said prongs; and maintaining said portion substantially flat throughout said steps.

29. The method of making lock washers which includes the steps of providing a section of stock having a plurality of separate adjacent marginal prongs and a continuous portion to which said prongs are joined; reducing the diameter of said includes' the steps of providing a section of stock having a plurality of separate adjacent marginal prongs and a substantially circular continuous portion to which said prongs are joined; providing a hole in said continuous portion; and reducing the diameter of said continuous portion to effect an overlapping of adjacent prongs.

32. The method of making lock washers which includes the steps of providing a section of stock havingan aperture therein and having a plurality of separate adjacent marginal prongs adjacent said aperture and a continuous portion to which said prongs are joined; and reducing the diameter of said portion to effect an overlapping of said adjacent prongs.

33'. The method of making lock washers of the type for application between parallel work surfaces which includes forming a plurality of radial slits along one margin of an annular washer blank whereby to provide a blank having a plurality of adjacent marginal prongs and a continuous circular portion to which said'prongs are attached, warping said prongs so as-to provide work engaging teeth thereon on opposite sides of the blank, and working the metal of said continuous portion to eifect an overlapping of adjacent prongs, radially contiguous parts of said con-.- tinuous portion being maintained in parallel planes during the working operation.

34. The method ofmaking lock washers which comprises forming a plurality of radial slits along the inner margin of an annular washer blank whereby to provide a blank having a plurality of adjacent marginal prongs along its inner margin and a continuous circular portion along its outer margin to which said prongs are attached, warping said prongs so as to provide work engaging teeth thereon on opposite sides of the blank, and

working the metal of saidcontinuous portion to eifect an overlapping of adjacent prongs.

35. The method of making lock'washers of the type for application between parallel work surfaces which includes marginally severing a flat type annular washer blank along one margin thereof to provide a blank having a plurality of adjacent marginal prongs and a continuous circular portion to which said prongs are attached,

warping said prongs so as to provide work engaging teeth thereon on opposite sides of the blank, and working the metal of said continuous portion to eifect a circumferential shifting of adjacent prong margins whereby to bring adjacent prongs into overlapping relation while maintaining theing of undiminished thickness with respect to the.

washer body.

ADOLF THODE.- 

